Ti3C2-based MXene anchoring single-atom Co as a long-lasting peroxymonosulfate activator enabling efficient water decontamination: Deciphering the critical role of titanium vacancies

Cobalt atoms anchored on Ti 3 C 2 -based MXene (i.e., Co-SA/MXene) have been successfully endowed with exceptional catalytic performance for the elimination of aqueous micropollutants. Herein, we firstly proposed a coupling method of etching-exfoliation-reduction to enrich titanium vacancies. The as-synthesized Co-SA/MXene exhibited a superior removal efficiency of ranitidine of 100 %, and the corresponding reaction kinetics constant (μmol/s•g) was 1.11–6643.53 times higher than the state-of-the-art for ranitidine degradation. The introduction of abundant titanium vacancies enabled a long-lasting life via an accelerated valence cycling of Co(II) and Co(III), and also effectively inhibited toxic Co 2 + leaching. DFT revealed that O II /O III dual-atoms were more suitable for PMS adsorbing while offering stronger adsorption energy, and further offered a new insight into the PMS activation mechanism for 1 O 2 selected generation. This work revealed that oxidation behavior of ranitidine and established an attractive water treatment technique for the rapid removal of aqueous micropollutants.